Using ruler and a pair of compasses only, 

(a) construct (i) a quadrilateral PQRS with /PS/ = 6 cm, < RSP = 9 cm, /QR/ = 8.4 cm and /PQ/ = 5.4 cm;   (ii) the bisectors of < RSP and < SPQ to meet at X ;                         (iii) the perpendicular XT to meet PS at T.

(b) Measure /XT/.